package chapter9;

import org.bouncycastle.cms.*;

import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import java.util.Arrays;

/**
 * Demonstrate creation and processing a key-encrypted key enveloped-message.
 */
public class KEKEnvelopedDataExample {
    public static void main(String[] args)
            throws Exception {
        KeyGenerator keyGen = KeyGenerator.getInstance("DESEDE", "BC");
        SecretKey key = keyGen.generateKey();

        // set up the generator
        CMSEnvelopedDataGenerator edGen = new CMSEnvelopedDataGenerator();

        byte[] kekID = new byte[]{1, 2, 3, 4, 5};

        edGen.addKEKRecipient(key, kekID);

        // create the enveloped-data object
        CMSProcessable data = new CMSProcessableByteArray("Hello World!".getBytes());

        CMSEnvelopedData enveloped = edGen.generate(
                data,
                CMSEnvelopedDataGenerator.AES128_CBC, "BC");
        // recreate
        enveloped = new CMSEnvelopedData(enveloped.getEncoded());

        // look for our recipient
        RecipientId recId = new KEKRecipientId(kekID);
        
        /*RecipientId     recId = new RecipientId();

        recId.setKeyIdentifier(kekID);*/

        RecipientInformationStore recipients = enveloped.getRecipientInfos();
        RecipientInformation recipient = recipients.get(recId);

        if (recipient != null) {
            // decrypt the data
            byte[] recData = recipient.getContent(key, "BC");

            // compare recovered data to the original data
            if (Arrays.equals((byte[]) data.getContent(), recData)) {
                System.out.println("data recovery succeeded");
            } else {
                System.out.println("data recovery failed");
            }
        } else {
            System.out.println("could not find a matching recipient");
        }
    }
}